In space, nobody can hear you freestyle. But that hasn't stopped some of hip-hop's greatest legends from appearing in some classic science fiction and fantasy movies. From battling killer sharks to fighting off ghosts on Mars, some of our favorite rappers have also become some of our favorite SF heroes.

Honorable mentions: Xzibit, who was in X-Files: I Want To Believe, and Busta Rhymes, who was in Halloween: Resurrection.

10) Ice Cube (Ghosts of Mars)
Okay, so one of these days I'm really going to write my essay about how Ice Cube's movie Friday is really an adaptation of Heinlein's novel of the same name. But even leaving that aside, his role in Ghosts of Mars is absolutely fantastic. It's a lesbian-dominated future Mars, but Ice Cube is still the same guy, and he has to team up with Natasha Henstridge to battle the spirits on Mars. Plus he gets to shout, "Come on, you mindless motherfuckas!" It's awesome stuff.

9) Snoop Dogg (Bones)Bones is actually a massively underrated horror film that blends an homage to blaxploitation with themes of gentrification and drug addiction. And Snoop Dogg is amazingly watchable, and actually turns in a pretty great performance, as Jimmy Bones, the kingpin who tried to keep his neighborhood clean, only to be betrayed and murdered — and now he's back for revenge.

8) Will i Am (X-Men Origins: Wolverine)
Thanks to SupaChupacabra for suggesting this one. Will i Am is totally indispensible in X-Men Origins: Wolverine, as John Wraith, who rocks a cowboy hat and teleports in and out of crazy mutant mayhem. Just watch this awesome featurette, where John Wraith introduces himself. Will i Am also appeared in Joan of Arcadia, and served as a Jedi election commentator via hologram during election 2008.

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7) Common (Terminator Salvation, Wanted, Justice League)
If that Justice League movie had gotten made, and Common had gotten to play John Stewart (aka Green Lantern), then he'd deserve a much higher spot on this list. As it is, he still gets props for playing one of the gang of assassin trainers in Wanted. And he was fine in Terminator Salvation.

6) Mos Def (Hitchhiker's Guide to the Galaxy, Yo Gabba Gabba!)
The big-screen Hitchhiker's movie was a bit of a letdown, all told — but Mos Def was pretty great as Ford Prefect. He also was terrific in the quasi-science-fictional Be Kind Rewind. But he really wins MVP status for his role on Yo Gabba Gabba! as Super Mr. Superhero.

5) Ice-T (Tank Girl, Leprechaun in the Hood, Batman Beyond)
He totally went for it as the kangaroo dude in Tank Girl, the movie adaptation of the freaky dystopian future comic series. He's a gangsta in the equally freaky Leprechaun in the Hood, in which he has to face down a murderous creature of folklore. And then there's his role as Ramrod in Batman Beyond, which totally seals the deal.

4) Ludacris (Gamer, Max Payne, Fred Claus)
Mostly we love him for his role as the conscientious objector dude in Gamer, who is the one guy who says no to having neurological implants to let Dexter control him. But it's worth noting that he's also DJ Donnie in Fred Claus, where he puts on an elf costume and performs the grating but ear-wormy "Ludacrismas".

3) L.L. Cool J (Rollerball, Deep Blue Sea, Toys)
He actually survives to the end of Deep Blue Sea! Here's the final 10 minutes of the movie to prove it. He goes head-to-mutated-head with some messed-up killer sharks that already ate Samuel L. Jackson, and he lives to rap about it at the end. Too bad he shoots that guy in the leg by mistake. Oh, and he's pretty great in Toys, with his weird anti-photocopying crusade. We've blotted the Rollerball remake out of our memories.

2) Mark Wahlberg (Planet of the Apes, Max Payne, The Happening)
Okay, so he hasn't exactly been in our favorite science fiction movies of all time — the Planet of the Apes remake was hideous enough, but then he had to come back with Max PayneandThe Happening. But just think how much more painful those films would have been with a less lovable mug in the role. And nobody says, "What?... No" like Marky Mark. It's such a great line, it's even become a rap song.

1) Will Smith (Independence Day, Men In Black, I, Robot, Hancock, I Am Legend, etc.)
He's arguably the most bankable actor in science fiction, and it's easy to forget that Will Smith started out as one half of DJ Jazzy Jeff and the Fresh Prince. He can turn almost anything into a hit — just look at Hancock. Although even Will Smith can't commit suicide by jellyfish and turn that into a massive hit movie.